The present invention concerns clamping mechanisms for holding cutting inserts on toolholders during material removal operations.
A toolholder usually is comprised of a shank for attachment to a machine and a pocket on one end for seating of a cutting insert, usually an indexable cutting insert. The insert on the toolholder must always be firmly and positively located in order to provide as consistent a cut in the work material as possible.
In some cases, the clamping mechanism can take the form of an external clamp that is located on top of the toolholder and extends over the top of the insert to provide sufficient clamping force to hold the insert in the pocket.
Sometimes, however, external clamping mechanisms are not satisfactory because of the smallness in size of the insert or because of the amount of work space allowed for specific cuts.
When the external top clamps are not satisfactory, usually the cutting insert can be made with an axial hole through its center and placed over a rotatable pin element that is held by the toolholder. When using a pin, the insert is usually held firmly between the head of the pin and a side wall of the pocket of a toolholder.
Various mechanisms for providing the pin with enough force to hold the insert in the toolholder have been devised, a representative sampling of which may be had by reviewing U.S. Pat. No. 3,525,136 to Crosby; U.S. Pat. No. 3,787,941 to Novkov; U.S. Pat. No. 3,491,421 to Holloway; U.S. Pat. No. 3,488,422 to Jones; and U.S. Pat. Nos. 3,341,920 and 3,341,923 to Kelm. In addition, attention should be directed to U.S. Pat. Nos. 3,946,473; 3,623,201 and 3,310,859 for similar types of pin holding mechanisms.
While some of the above-mentioned clamping mechanisms have worked adequately, there is always a need to improve upon the efficiency and reliability of the clamping mechanism.
It is an object of the present invention to provide a stronger pin clamping mechanism.
It is a further object of the present invention to provide a more positive and faster acting pin clamping element.